Final answer:
The Oral Stage, occurring from birth to 1 year, is characterized by sucking and swallowing. This stage involves pleasure focused on the mouth and activities such as eating and sucking on objects.
Step-by-step explanation:
The Oral Stage, which occurs from birth to 1 year, is characterized by sucking and swallowing. During this stage, pleasure is focused on the mouth, and infants experience pleasure from activities such as eating and sucking on objects like nipples, pacifiers, and thumbs. According to Freud, an adult who engages in behaviors such as smoking, drinking, or overeating may be fixated in the oral stage due to unresolved conflicts during this period of psychosexual development.